1. Field of the Invention
The present invention relates to a press fabric for a machine for the production of web material, specifically paper or cardboard, and to a method to produce said press fabric.
2. Description of the Related Art
A press fabric of this type generally includes a carrying structure, for example, in the embodiment of a woven or randomly laid structure, or a so-called spiral-link structure. On one side of this carrying structure in contact with the web material, fibrous material, which may be in the form of several layers of fibrous material, is provided and is generally tightly bonded with the carrying structure by means of needling. Press fabrics of this type, which may be provided in an endless configuration, are utilized first and foremost in so-called press sections in paper machines where the press fabrics are moved through press nips together with the web material which is being produced. During this process, liquid is squeezed from the web material and absorbed by, or removed through the press fabric. In order to improve the liquid absorption capacity of the press fabric, a layer, which has a comparatively high hollow space volume in which the water that is pressed out of the web material can be absorbed, is provided in a known method between the carrying structure and one fibrous layer which represents a web material contact surface. These layers may also be in the form of a woven fabric. This, of course, has the disadvantage that due to the location of a fabric layer relatively near the web material contact surface, the fabric structure marks the web material which is to be produced. A known alternative is the introduction of polymeric material membranes or membranes of similar types of material which are designed essentially with a plain surface and a multitude of openings. These membranes are, however, expensive to produce.
A press fabric for a machine for the production of web material, especially paper or cardboard, as well as a method for the manufacture of a press fabric of this type with which the volume for liquid absorption can be increased without the risk of marking the web material that is to be produced.
What is needed in the art is a press fabric for a machine for the production of web material, especially paper or cardboard, as well as a method for the manufacture of a press fabric of this type with which the volume for liquid absorption can be increased without the risk of marking the web material that is to be produced.